Updated on November 24, 2020
Neurons are the basic building blocks of the nervous system. These specialized cells are the information-processing units of the brain responsible for receiving and transmitting information. Each part of the neuron plays a role in communicating information throughout the body.
Neurons carry messages throughout the body, including sensory information from external stimuli and signals from the
brain to different muscle groups in the body. In order to understand exactly how a neuron works, it is important to look at each individual part of the neuron. The unique structures of the neuron allow it to receive and transmit signals to other neurons as well as other types of
cells. Dendrites are tree-like extensions at the beginning of a neuron that help increase the surface area of the cell body. These tiny protrusions receive information from other neurons and transmit electrical stimulation to the soma. Dendrites are also covered with synapses. Characteristics
Most neurons possess these branch-like extensions that extend outward away from the cell body. These dendrites then receive chemical signals from other neurons, which are then converted into electrical impulses that are transmitted toward the cell body. Some neurons have very small, short dendrites, while other cells possess very long ones. The neurons of the central nervous systems have very long and complex dendrites that then receive signals from as many as a thousand other neurons. If the electrical impulses transmitted inward toward the cell body are large enough, they will generate an action potential. This results in the signal being transmitted down the axon. SomaThe soma, or cell body, is where the signals from the dendrites are joined and passed on. The soma and the nucleus do not play an active role in the transmission of the neural signal. Instead, these two structures serve to maintain the cell and keep the neuron functional. Characteristics
Think of the cell body as a small factory that fuels the neuron. The soma produces the proteins that the other parts of the neuron, including the dendrites, axons, and synapses, need to function properly. The support structures of the cell include mitochondria, which provide energy for the cell, and the Golgi apparatus, which packages products created by the cell and dispatches them to various locations inside and outside the cell. Axon HillockThe axon hillock is located at the end of the soma and controls the firing of the neuron. If the total strength of the signal exceeds the threshold limit of the axon hillock, the structure will fire a signal (known as an action potential) down the axon. The axon hillock acts as something of a manager, summing the total inhibitory and excitatory signals. If the sum of these signals exceeds a certain threshold, the action potential will be triggered and an electrical signal will then be transmitted down the axon away from the cell body. This action potential is caused by changes in ion channels which are affected by changes in polarization. Characteristics
When a signal is received by the cell, it causes sodium ions to enter the cell and reduce the polarization. If the axon hillock is depolarized to a certain threshold, an action potential will fire and transmit the electrical signal down the axon to the synapses. It is important to note that the action potential is an all-or-nothing process and that signals are not partially transmitted. The neurons either fire or they do not. AxonThe axon is the elongated fiber that extends from the cell body to the terminal endings and transmits the neural signal. The larger the diameter of the axon, the faster it transmits information. Some axons are covered with a fatty substance called myelin that acts as an insulator. These myelinated axons transmit information much faster than other neurons. Characteristics
The myelin surrounding the neurons protects the axon and aids in the speed of transmission. The myelin sheath is broken up by points known as the nodes of Ranvier or myelin sheath gaps. Electrical impulses are able to jump from one node to the next, which plays a role in speeding up the transmission of the signal. Axons connect with other cells in the body including other neurons, muscle cells, and organs. These connections occur at junctions known as synapses. The synapses allow electrical and chemical messages to be transmitted from the neuron to the other cells in the body.
Terminal Buttons and SynapsesThe terminal buttons are located at the end of the neuron and are responsible for sending the signal on to other neurons. At the end of the terminal button is a gap known as a synapse. Neurotransmitters are used to carry the signal across the synapse to other neurons. When an electrical signal reaches the terminal buttons, neurotransmitters are then released into the synaptic gap. Characteristics
A Word From VerywellNeurons serve as basic building blocks of the nervous system and are responsible for communicating messages throughout the body. Knowing more about the different parts of the neuron can help you to better understand how these important structures function as well as how different problems, such as diseases that impact axon myelination, might impact how messages are communicated throughout the body. Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Additional Reading
By Kendra Cherry
Thanks for your feedback! What are the billions of nerve cells that make up the brain called?Your brain contains billions of nerve cells, called neurons, which make a very large number of connections with specialized parts of other neurons, called dendrites, to form networks.
How do drugs relate to the process of neural transmission?Drugs interfere with the way neurons send, receive, and process signals via neurotransmitters. Some drugs, such as marijuana and heroin, can activate neurons because their chemical structure mimics that of a natural neurotransmitter in the body. This allows the drugs to attach onto and activate the neurons.
What layer of fatty tissue protects axons?The myelin sheath is a layer of fatty tissue surrounding the axon of a neuron that both acts as an insulator and allows faster transmission of the electrical signal.
What is the fatty substance that coats neural pathways called quizlet?Myelin. fatty substances produced by certain glial cells that coat the axons of neurons to insulate, protect, and speed up the neural impulse.
|